Process of making protocatechuic aldehyde.



UNITED STATES PATENT ()EEJIOE.

RUDOLF J OHANN MARIA SOHMER, OF VIENNA, AUSTRIA-HUNGARY,

ASSIGNOR TO THE FIRM OF FRANZ FRITZSCHE & 00., ()F HAMBURG- UHLEN HORST,GERMANY.

PROCESS OF MAKING PROTOCATECHUIO ALDEHYDE.

Specification of Letters Patent.

Patented Nov. 14, 1905.

Applicati fil d August 15,1904. Serial No. 220,851.

i fites, or chlorids of metals, at twelve atmosringerstrasse 59, in thecity of Vienna, Austria-Hungary, have invented new and usefulImprovements in the Manufacture of Protocatechuic Aldehyde, of which thefollowing is a specification.

This invention relates to the manufacture of i protocatechuic aldehydeintended to be used as raw material in the manufacture of vanillin andother chemicals.

According to a scientific publication heliotropin with hydrochloric acidof one per cent. gives when heated to a temperature of 200 centigradeprotocatechuic aldehyde, carbon being at the same time separated. sureof fourteen atmospheresthat is to say, at a temperature of about 195 to200 centigrade heliotropin begins to be carbonized; but nevertheless noextraction of protocatechuic aldehyde on a large scale is possible, onlytraces of it unfit for any technical purpose being obtained. It has beenfound that dilute acids, which,however,can be replaced by solutions ofacid salts, such as bisulfates, bisul- Ct-HdlggOH HOH Heliotropin.

It has been found that specially-favorable results are obtained by usingbisulfites, in presence of which water acts as a solvent. For instance,ten kilograms of heliotropin are heated with one hundred and fortyliters of water and fourteen kilograms of bisulfite of sodium in anautoclave, as stated above. in order to separate the protocatechuicaldehyde, either the greater volatility of heliotropin is utilized byblowing off the heliotropin from (1)COH,NaHSO3 can HOH mo Heliotropinbisulfite. Water.

Or the protocatechuic aldehyde may be precipitated after neutralizationby means of salts of lead from which it is liberated, say,

At a pres- 1 pheres---that is to say,at about 185 to 19O centigrade-andat a lower pressure or temperatu re easily produce the decomposition ofheliotropin into protocatechuic aldehyde, so that nearly the wholetheoretical yield is obtained.

For carrying out the process based on the above heliotropin is heated,say, with hydrochloric acid of one per cent, the whole being continuallystirred, without exceeding a pressure of twelve atmospheres or atemperature of 190 centigrade.

Example: Forty parts of hcliotropin, eight hundred parts of water, andtwenty parts of merchantable hydrochloric acid are heated for three andone-half hours at live atmospheres (150 centigrade) and give twentyparts of pro- 'ater with hydrochloric acid.

tocatechuic aldehyde and 17.2 parts of heliotropin. The proportion ofprotocatechuic aldehyde extracted can be further increased by carryingout the process with heliotropin in solution. Thus, for instance,heliotropin may be dissolved in hydrocarbons or in alcohol, and thereagents specified are then applied. The decomposition of theheliotropin with water in the presence of acid is shown by the followingequation:

COHU) O can one) HC OHM) H Protoeatechuic l-ormaldealdehyde. hyde.

the product of reaction after neutralization and by extractingprotocatechuic aldehyde by evaporation, or the product of reaction isneutralized and heliotropin is extracted by means of others, and thenafter acidulating the protocatechuic aldehyde is finally extracted. Thedecomposition of the heliotropin combined With sodium bisullite withwater, wherein the bisultite acts as an acid agent, is shown in thefollowing equation:

COH(1) O (JfiHS 011(3) H0 ---,NaHSO.;

one) H Protocateehuie Formaldehyde bisulfite.

aldehyde.

by sulfureted hydrogen, and finally obtained by evaporation from thewater solution.

Protocatechuic aldehyde thus obtained forms a cheap raw material for themanufacture of vanillin and other chemical compounds.

Having thus described my invention, I claim- 1. The process ofmanufacturing protocatechuic aldehyde, which consists in heatingheliotropin with an acid agent in the presence of water under a pressurenot exceeding twelve atmospheres and under a temperature not exceeding190 centigrade, substantially as described.

2. The process of manufacturing protocatechuic aldehyde, which consistsin heating heliotropin in the presence of water and an acid salt asbisulfite of sodium under a pressure not exceeding twelve atmospheresand under a temperature not exceeding 190 centigrade, substantially asdescribed.

3. The process of man ufacturing protocatechuic aldehyde, which consistsin heating heliotropin with an excess of bisulfite of sodium, and anexcess of water under a pressure not exceeding twelve atmospheres andunder a temperature not exceeding 190 centigrade, and separating theprotocatechuic aldehyde from the resulting product, substantially asdescribed.

4. The process of manufacturing protocatechuic aldehyde, which consistsin dissolving heliotropin, mixing it with an acid agent and water, andheating the mixture under a pressure not exceeding. twelve atmospheres,and under a temperature not exceeding 190 centigrade, substantially asdescribed.

5. The process of manufacturing protocatechuic aldehyde, which consistsin dissolving heliotropin, mixing the solution with sodium bisulfite,and a large excess of water, heating the mixture under a pressure notexceeding twelve atmospheres, and under a temperature not exceeding 190centigrade, substantially as described.

6. The process of manufacturing protocatechuic aldehyde, which consistsin dissolving heliotropin in alcohol, mixing the solution with an excessof bisulfite of sodium and a large excess of water, heating the mixtureunder a pressure not exceeding twelve atmospheres, and under atemperature not exceeding 190 centigrade, and separating theprotocatechuic aldehyde from theresulting product, substantially asdescribed.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

RUDOLF JOHANN MARIA SOMMER. Witnesses:

ERICH BADERLE, ALoIs FISCHER.

